A novel design of capacitive MEMS pressure sensor for lubricating system

This paper presents a novel comb drive based MEMs capacitive pressure sensor for measuring the pressure inside the lubricating system. The working principle and design analysis of the proposed MEMS comb drive capacitive sensor is explained. The diaphragm thickness is a primary factor in determining the pressure sensor sensitivity. MEMS technology allows diaphragm to be very thin compared to conventional machining. This comb drive capacitive pressure sensor isolates the pressure sensing diaphragm from its capacitance sensing movable comb plate by a mechanical coupling so that it increases the pressure sensitivity. The design and simulation of the sensor is analysed using Comsol Multiphysics 4.4. The stress distribution of the membrane and capacitive sensitivity analysis is carried out for the range of pressure from 0 to 10 bar. The dimension of the Capacitor plate with comb is 200μm ×200μm ×3 μm. The sensor works efficiently in the range of 30°C to 270°C. The main purpose of the novel design is even a small change in the capacitance in the range of atto farad (aF) can be sensed accurately by this model.